Device for utilizing the heat contained in the fuel residues of furnaces



A155128, 1'925. 1,535,755 C. CHRISTIANS DEVICE FOR UTILIZING THE HEATCONTAINED IN THE FUEL RESIDUES OF FURNACES Filed Aug. 29, 1921llllllllllllllllllIlllllllll `hitherto been lost.

Patented Apr. 28, 1925.

UNITED ,STAT

PATENT OFFICE.

DEVICE Foa TJ'IILIZING` THE HEAT CONTAINED 1N THE runnansrnuas yornuisances.

Application fue@ August as, 1921. serial No. 496,653.

low-grade fuel is used, much depends also upon the size of thecoal-pieces. In the case of these latter being different, the slag maycontain-a considerablepercentage of unconsumed and still utilizablefuel,`from which an adequate amount of heat might have been produced.`This heat, as well as that contained in the glowing slag, has Moreover,the said residues are troublesome because the heat they radiateincommodes the attendant, the

upon it. The amount `of heat thus lostis particularly great also fromthe reason that, especially with mechanical ygrates, the feed of thegrate depends not only upon the combustion of the fuel or its residues,but also, andein fact, primarily upon the necessary efficiency of thefurnace and the inflammability of the fuel. v y

`The object of the present :invention is to utilize the heat stillcontained in, and to be produced by, the residues `in question, viz, theslag and the remainders of the fuel, and that object is attained byconducting the combustion-air wholly or partly first to the residueswhich lie upon a secondarygrat'e and then to the fuel which lies uponthe primary grate, as is more fully described hereinafter. y The glowingslag is, by this manner of operation, cooled down and thefuel-remainders contained in and accompanying it, are

completely burned and consumed. The combustion-air, inpassing though andover the secondary grate, takes up the heat contained in the slag andproduced by the combustion of the c'o'al pieces and carries it to theprimary grate where it` is appropriately utilized. l

The success of` this preheating of the air consists not solely ingaining the heat from the residues, but also in transferring thecombustion-teniperature to a higher `zone, further in doing away withtoo great an excess of air in the furnace-space proper, and, finally, indiminishing the chimneylosses.

This manner of operation may be further impro-ved by using thecombustion-air at the same time for cooling the side-walls andside-coverings of the furnace which are exposed to danger' because ofthe high temperature existing in the furnace-space. The combustion-air,after having been preheated, is for that purpose, led through hollowspaces provided in the said sidewalls and coverings, as is also morefully described hereinafter. y

Instead of leading the whole quantity of the prefheated air through thesaid spaces, only a part of it need be employed for that coolingpurpose. t

The invention, although chiefly intended for furnaces with travellinggrates, may be used also in connection with furnaces with stationarygrates fed by hand.

In order to make my invention more clear, I refer tothe accompanyingdrawings, in which Figure 1 is a vertical longitudinal section through afurnace having a travelling grate and being furnished with and operatingaccording to my invention.

Figure 2, is a horizontal section through the front part of the saidfurnace.

Referring to yFigures l and 2, the second--` ary grate 2 is fed from theprimary grate l, the slag being then cooled upon the grate 2 and thecoal-remainders being burnt upon it. The combustion-air necessary forthe whole amount of the fuel is first led to and ythen iiows in thedirection of the arrows 3 from the grate 2 to the grate l where it`serves to burn the fuel lying upon this grate.

In order tocoinpel the air to pass from the grate 2 beneath thegrat-el,- a hbrzbntai Wall 8 is,V provided which prevents the air fromdirect entry to the furnace abovethe grate l. Said Wall or plate 8 maybe stationary or movable.

In the forni of construction shown in Figures l and 2, the pre-heateda-i-r does not pass directly from the furnace grate 2 tothe furnace l,but indirectly, in that it is inadeto flow through spaces' l provided inthe side-walls. The arrows 5 Figure l indicate the direction of theseair currents.

The side-Walls and side-coverings are thus cooled, as already mentioned.

G is an auxiliary channel which is provided, Where only a part of thecombustionair is to be pre-heated. The other part then flowsv in thedirection indicated by the arrow 7 through the said channel G' directlyto the primary grate l. v

Having now described iny invention, what I desire to secure by a patentof the United States is:

l. In a furnace, the combination, with a travelling` grate, of asecondary, grate adapted to receive the residues from the saidtravelling grate; a conduit adapted to lead combustion-air to the saidsecondary grate; and a conduit adapted to lead the heated mixture of thesaid air and the combustiongases from the secondary grate to thetravelling grate, for the purpose as described.

2. ln a furnace, the combination, with a `ravelling gij-ate, of asecondary grate adapted to receive the residues froin the saidtravelling grate; a wall arranged between the furnace spa-ce containingthe said grates; a conduit adapted to lead combustion-air to thesecondary grate; and a conduit adapted to lead a mixture of said air andthe combustion-gases in a preheated state from the secondary grate tothe travelling grate, for the purpose as described.

In a furnace, the combination, with a travelling grate, of a secondarygrate at the end of the travelling grate and adapted to receive theresidues from the said travelling grate; a conduit adapted to leadcoinbustion-air to the secondary grate; a conduit provided in theside-Walls of the furnace and being connected at one end with thefurnace-space containing the secondary grate and at the other end Withthe furnacespace containing the travelling grate, for the purpose asdescribed.

In testimony whereof I have hereunto set my hand in the presence of theundersigned Witnesses, at Berlin, Germany, this 10th day of August,1921.

CHRISTIAN CHRISTIANS. lVitnesses:

Gis-one HiRscHFELD, RICHARD ANDREA.

